Respiratory assistance masks are already known, to be able to bring in the lungs of a patient respiratory gas from an external source, said respiratory masks comprising:
a hollow body, the internal volume defines a chamber provided with a respiratory gas inlet formed with a tip being integral with the body bottom able to be connected with said source, the hollow body being adapted to be applied against the patient's face while enclosing the nose and/or the mouth of the latter;
an opening forming the respiratory gas outlet and adapted to be connected with patient's respiratory tract; and
a flexible bearing member—for example under the shape of an inflatable bead or a closed pore foam bead—bordering the contour of said opening and adapted to abut against patient's face so as to provide sealing between said respiratory gas outlet and the outside.
Furthermore, it is known that the flexibility of the bearing member confers to the hollow body a certain freedom of orientation once the mask being positioned on the patient's face. In other words, the bearing member provides an orientation function in the hollow body space, thereby allowing for a manipulation of the latter with no discomfort for the patient.
However, despite its flexibility, such a bearing member cannot perfectly meet some irregularities of patient's face, on which it is applied so that:
leaks locally occur, leading to expensive losses of respiratory gas; and
there is a risk that respiratory gas, passing between the bearing member and the face further to sealing defects, enters patient's eyes, generating ocular irritations and conjunctivities.
To alleviate such sealing defects, the application force of the mask on the face is generally increased—for example thru elastic straps passing behind patient's head—so as to be able to press the bearing member against the face.
However, despite the fact that it favors the appearance of scabs, the thorough application of the respiratory mask on patient's face leads to a large pressure of the flexible bearing member, thereby tending to make it more rigid. Due to the loss of the flexibility thereof, the bearing member only provides a limited orientation of the hollow body relative to the face.